A core idea of cloud computing is to managing and scheduling, in a unified manner, large quantities of computing resources that are connected by using a network, to constitute a computing resource pool to provide a resource and a service for a user according to a user demand. A network providing such a computing resource is called cloud.
A cloud platform is a platform that provides a cloud-based service for an application developer. A PaaS (Platform as a Service) is a common cloud platform and belongs to a common service mode of generalized cloud computing, where the generalized cloud computing means that a developer obtains a required service by using a network in an on-demand easy-to-extend manner. The PaaS provides a middleware platform that is developed in a customized manner, for a user as a service. Essentially, the PaaS converts a resource and a service of the Internet into a programmable interface, to provide a third-party developer with a resource and service platform that has commercial value. The middleware platform, also called a platform node, is a general service having a standard program interface and protocol, and is usually located between hardware and an application or between an operating system and an application. A PaaS CSP (Cloud Service Provider) provides a variety of middleware platforms, for example, an application server and a database. A CSP can design, develop, and optimize a platform node, and an application developer only needs to focus on development of an application node on the platform node, which brings a great convenience to development.
However, the PaaS CSP currently provides an application developer only with a platform node of a fixed version, and maintains a version of a platform node for all applications. If the application developer needs to upgrade an application node, but an upgraded application node has a requirement for the version of the platform node, and if the version of the platform node cannot meet the requirement of the upgraded application node, the application node fails to be updated, and an application cannot run normally.